This invention relates to polymers crosslinked by means of methacrylaldimine linkages or crosslinking groups. The methacrylaldimine crosslinking groups are produced by reaction of vinyl addition homopolymers or copolymers of methacrolein and compounds having at least two primary amine or primary amine-generating, such as aldimine or ketimine, groups. The crosslinking occurs, preferably at ambient temperatures or at elevated temperatures, to produce a crosslinked polymer.
Neher et al, U.S. Pat. No. 2,416,536, teaches the copolymerization of acrolein and methacrolein with acrylic compounds, such as the acid, esters, nitrile, and amides. Neher further teaches that the copolymers containing 10% or more of acrolein or methacrolein are vulcanizable with sulfur. Larsson et al, U.S. Pat. Nos. 3,896,085 and 4,016,127, teach the treatment of leather with copolymers containing acrolein and the curing of these with a poly-primary amine.
The new methacrylaldimine crosslinked polymers are surprisingly superior to acrylaldimine crosslinked polymers in several properties, such as resistance to thermal degradation, resistance to water and aqueous solutions and color stability. Formulations of methacrolein polymers with poly-primary amines have much longer, and thus more useful, pot lives than do the corresponding acrolein polymer formulations.